Aberrant p53 alters DNA damage checkpoints in response to cisplatin: Downregulation of CDK expression and activity

Label-free spatiotemporal decoding of single-cell fate via acoustic driven 3D tomography

Label-free three-dimensional imaging plays a crucial role in unraveling the complexities of cellular functions and interactions in biomedical research. Conventional single-cell optical tomography techniques offer affordability and the convenience of bypassing laborious cell labelling protocols. However, these methods are encumbered by restricted illumination scanning ranges on abaxial plane, resulting in the loss of intricate cellular imaging details. The ability to fully control cellular rotation across all angles has emerged as an optimal solution for capturing comprehensive structural details of cells. Here, we introduce a label-free, cost-effective, and readily fabricated contactless acoustic-induced vibration system, specifically designed to enable multi-degree-of-freedom rotation of cells, ultimately attaining stable in-situ rotation. Furthermore, by integrating this system with advanced deep learning technologies, we perform 3D reconstruction and morphological analysis on diverse cell types, thus validating groups of high-precision cell identification. Notably, long-term observation of cells reveals distinct features associated with drug-induced apoptosis in both cancerous and normal cells populations. This methodology, based on deep learning-enabled cell 3D reconstruction, charts a novel trajectory for groups of real-time cellular visualization, offering promising advancements in the realms of drug screening and post-single-cell analysis, thereby addressing potential clinical requisites.

Betaine downregulates microRNA 34a expression via a p53-dependent manner in cisplatin-induced nephrotoxicity in rats

Cisplatin-induced nephrotoxicity limits its wide application as a chemotherapeutic drug. Betaine is a natural trimethylglycine compound involved in several biological reactions. In this study, the protective effect of betaine against cisplatin-induced nephrotoxicity through modulating the expression of microRNA 34a (miRNA 34a), p53, apoptosis, and inflammation was investigated. Adult Wistar rats were divided into normal group (received vehicle); betaine group (received 250 mg betaine/kg BW/day via oral gavage from Day 1 to Day 25); cisplatin group (received a single intraperitoneal dose of cisplatin at 5 mg/kg BW on Day 21) and betaine + cisplatin group (received the same doses of betaine and cisplatin). The results demonstrated that the cisplatin group exhibited severe kidney tissue damage and an increase in blood creatinine and urea levels. Furthermore, the cisplatin group showed a significant upregulation of miRNA 34a and higher levels of phospho-p53, caspase 3, cytochrome c, NF_k B, and IL-1β compared to the normal group. Remarkably, the betaine + cisplatin group showed significantly decreased blood creatinine and urea concentrations, decreased levels of miRNA 34a, phospho-p53, caspase 3, cytochrome c, NF_k B, and IL-1β as well as improved kidney tissue integrity compared to the cisplatin group. In conclusion, cisplatin-induced nephrotoxicity in rats was associated with upregulation of miRNA 34a expression, apoptosis, and inflammation in p53-dependent manner. These effects were reversed by betaine administration that ultimately improved the kidney function and tissue integrity.

Inhibition of coiled coil domain containing protein 69 enhances platinum-induced apoptosis in ovarian cancer cells

Cisplatin is a platinum-based drug that is used for the treatment of human gynecological cancers. However, molecular mechanisms of chemo-resistance in ovarian cancer are poorly understood. The aim of the study is to examine the role of coiled coil domain containing protein 69 (CCDC69) in the underlying mechanism of chemoresistance. Heavy CpG methylation (73.1% and 74.3%) was found in A2780 and A2780cis cells assessing by bisulfite sequencing. Restoration in the expression of CCDC69 was found in A2780 and A2780cis cells after 5-Aza-dC treatment. In fact, the expression levels of CCDC69 were about 3-4 fold higher in cisplatin-resistant A2780cis cells than its parental cisplatin-sensitive A2780 cells. When knockout CCDC69 in cisplatin-resistant A2780cis and SKOV3 cells by CRISPR/Cas9, the CCDC69 knockout cisplatin-resistant A2780cis and CCDC69 knockout SKOV3 cells were also shown increased sensitive to cisplatin treatment. Moreover, treating CCDC69 knockout A2780cis cells with cisplatin, abrogated G1 and G2/M arrest, increased of cleaved caspase 3&8, greater ΔΨm loss and higher levels of Bax were observed. When restoring CCDC69 expression in CCDC69 knockout A2780cis cells by transient transfection, it attenuated sensitivity to cisplatin. By immunoblotting, we found that depletion of CCDC69 increased p53 acetylation at K382 site and Bax mitochondrial redistribution. Additionally, inhibition of c-Myc enhanced cisplatin sensitivities in CCDC69 knockout A2780cis cells, overexpression of c-Myc reduced apoptosis in CCDC69 knockout SKOV3 cells. Our results showed that CCDC69 inhibition might interfere with the effectiveness of combination therapy with platinum drugs.

Autoantibodies against p53 are associated with chromosome 17p deletions in chronic lymphocytic leukemia

Autoantibodies against p53 have been observed in many cancers, often linked with abnormalities in the TP53 gene. Since p53 mutations and deletions at chromosome 17p are known to occur in CLL, we measured anti-p53 autoantibodies by ELISA in plasma samples from patients with normal cytogenetics as well as those with 13q, 11q, and 17p deletions as well as trisomy 12. Anti-p53 autoantibodies were detected in over half of the patients with a 17p deletion but in very few of the others. There was no correlation between the levels of anti-p53 antibodies and the percentage of cells with 17p abnormalities. The levels of the anti-p53 autoantibodies remained stable for most patients with serial samples. Increased levels of antibodies that bound to two peptide fragments of p53 were also seen in patients with 17p deletions. At least on case with high levels of anti-p53 autoantibodies had a heterozygotic mutation known to result in a dominant negative phenotype, suggesting that aberrant expression of p53 may contribute to the development of autoantibodies and suggests that these autoantibodies may reflect biological features relevant to prognosis.

EPS8 upregulates FOXM1 expression, enhancing cell growth and motility

Previous studies from our laboratory have indicated that overexpression of the epidermal growth factor receptor pathway substrate 8 (EPS8) enhances cell proliferation, migration and tumorigenicity in vivo, although the mechanisms involved remain unexplored. A microarray screen to search for potential mediators of EPS8 identified upregulation of multiple cell cycle-related targets such as the transcription factor FOXM1 and several of its reported downstream mediators, including cdc20, cyclin B1, cyclin A, aurora-B kinase and cdc25C in cells with elevated EPS8, as well as matrix metalloproteinase-9, which we reported previously to be upregulated by EPS8-dependent mechanisms. Cells engineered to overexpress FOXM1 showed increased proliferation, similar to EPS8-overexpressing cells. Conversely, targeted knockdown of FOXM1 in EPS8-overexpressing cells reduced proliferation. Cotransfection of EPS8 with a FOXM1-luciferase reporter plasmid into 293-T- or SVpgC2a-immortalized buccal keratinocytes demonstrated that EPS8 enhances FOXM1 promoter activity, whereas chromatin immunoprecipitation assays revealed elevated levels of acetylated histone H3 associated with the FOXM1 promoter in cells expressing high levels of EPS8. Treatment of EPS8-overexpressing cells with inhibitors of phosphoinositide 3-OH kinase or AKT reduced expression of FOXM1 and aurora-B kinase, a transcriptional target of FOXM1. Overexpression of EPS8 induced expression of the chemokine ligands CXCL5 and CXCL12 in a FOXM1-dependent manner, which was blocked by LY294002 or a dominant-negative form of AKT. Additionally, overexpression of FOXM1 enhanced cell migration, whereas targeted knockdown of CXCL5 or inhibition of AKT reduced migration of EPS8-expressing cells. These data suggest that EPS8 enhances cell proliferation and migration in part by deregulating FOXM1 activity and inducing CXC-chemokine expression, mediated by PI3K- and AKT-dependent mechanisms.

Alterations in the p53 pathway and their association with radio- and chemosensitivity in head and neck squamous cell carcinoma

Chemotherapy and/or radiotherapy are established measures in treatment protocols of head and neck squamous cell carcinoma (HNSCC). However, we still lack reliable predictive markers for the response to radio- and chemotherapy. The p53 pathway is involved in stress response and thus might influence chemo-/radiosensitivity. Using 29 HNSCC cell lines previously characterized for p53 mutations, we simultaneously analyzed several key players in the p53 pathway by RT-PCR, transcript sequencing and immunohistochemistry, and investigated their association with chemosensitivity and radiosensitivity. Cell lines with p53 mutations were slightly more sensitive to cisplatin than those with wild-type p53. The type of mutation did not influence radio- or chemosensitivity. p14(ARF), an activator of p53, was lost or mutated in all cell lines. Three cell lines showed overexpression of HDM-2, a major negative regulator of p53; however, HDM-2 levels did not correlate with radio- or chemosensitivity. HPV-16 oncoproteins were detected in one highly chemoresistant cell line. Our findings suggest that molecular events resulting in the inactivation of the p53 pathway occur in all HNSCC cell lines. However, single alterations in the p53 pathway are not reliable predictors for the response to radio- or chemotherapy in HNSCC.